Stabilized heating fluid and method of stabilizing same



lo i siderableefiortfhas been directed to developrealisa- IAu so, 1932No Drawing.

sTaTss PANY, OF MIDLAND, MICHIGAN, A CORPORATION OF MICHIGAN STABILIZEDHEATING FLUID AND name]; or STABILIZING SAME Application filed July 13,

The present invention is concerned with and the like. It is concernedspecifically with a stabilized form of diphenyl oxide and a method forstabilizing diphenyl oxide.

The advantages arising from the use of a high point stable fluid asheating agent employing either the heated fluid or the vapor thereof hasbeen recently appreciated and coning methods of advantageously employingi 3 suchfluids.

Prominent among fluids proposed and in connection with which research.of considerable extent has been accomplished, is diphenyl oxide havingan atmospheric boiling point ap-.

proximating 500 F., and being fairly stable up to atemperature of 725 F.Diphenyl oxide hasideal properties for use as vapor in a heating orpower cycle or for use in the heated liquid form as a heating agent, andin indirect heating generally and in power cycles. It has been found,however, that some decomposition occurs during prolonged heating,particularly at temperatures above 725 F. It has been further found thatupon continuing the heating the rate of decomposition, as evidenced bythe change in atmospheric,

boiling point, falls off becoming less and less,

' y y and I have found that such falling off in the i tion of thediphenyl oxide by the accumularate of decomposition is caused by astabilizaposition, namely, diphenylene oxide. This latter substance hasa boiling point approximating 640 F. and has been found in the pure formto be stable up to a temperature of 1022 F. Other decomposition productsarising from the decomposition of diphenyl oxide are phenol and benzene.

The decomposition of diphenyl oxide upon prolonged heating at hightemperatures in- ,troduces a disadvantageousfactor into its use as aheating fluid for which it is in allother respects most admirably suitedand the overcoming of such decomposition tendency is a highly desirableend.

To the accomplishment of the foregoing and related ends, the invention,then, consists 1929. serial no. 378,182.

in the claims, the following description setting forth in detail severalmodes of carrying out the invention, such disclosedinode's illustrating,however, but several of various Ways in which the principle of.theinvention may be used. it

' My 'nvention consists in adding initially tothe diphenyl oxide aquantity of diphenyl ene' oxide, the quantity so added being in theapproximate proportion that would eventually be formed during prolongeduse ofv such diphenyl oxide in the particular apparatus or heating cyclefor which it is intended. The presence of suchdiphenylene oxide in themixture so formed with diphenyl oxide acts by mass action to push theequilibrium in the decomposition reaction toward the diphenyl oxide sidethereof, thereby eliminating or substantially restricting the formationof diphenylene oxide by decomposition of the diphenyl oxide. I findfurther that, for most purposes employing temperatures of the soprepared mixture in the range 600 F. to 800 F., a mixture of diphenyloxide and diphenylene oxide in the ratio of 70 to parts by weight willinsure the practically complete stabilization of the diphenyl oxide.When a diphenylene-oxide diphenyl-oxide mixture'is boiledin theconventionaldrum type boiler, it is obvious that the vaporcompositionwill differ from the residual liquid compositiomand it isalso obvious that, depending upon the ratio of the residual liquidvolume to the vapor volume, such change in 1 composition may proceed togreater or less extent. If a large portion of the mixture is present inthe system as vapor, the residual unvaporized liquid willbecome markedlycon-.

centrated as to diphenylene oxide content. If the proportion of themixture in the vapor form in the system is small such concentration willbe less marked.

It will accordingly be desirable to adjust the ratio of diphenyleneoxide added to the diphenyl oxide to compensate for the volume ratioconditions in the system in which the mixture is employed. 7

. The stabilizing action of diphenylene,

rricsf HERBERT H. now, or MIDLAND, MICHIGAN, AssIeNon TO THE rowcnnmrcar. COM-.

oxide may be also applied to mixtures of diphenyl oxide with othersubstances desirably added thereto to affect advantageouslyitsboiling'point or freezing point, such for instance, as diphenyl,naphthalene, etc. The stabilizing action will be secured by adding tosuch mixture diphenylene oxide, which will exert in the mixture thedescribed stabilizing action of the diphenyl oxide component thereof. lr 1 Other modesof applying'the principle of my invention may be employedinstead of the one explained,' change being made as re gards thematerials'or stepsemployed, pro,- vided the ingredients or steps statedby any of the following claims or the equivalent of a suchstatedingredients orsteps be employed. a I therefore particularly point outand dis- Y tinctly claim as my invention; 7

1. A stabilized heating fluid containing diphenyl oxide to which hasbeen added-dixphenylene oxide. 1 7 e, 2. A stabilized heating fluidcomprising V diphenyl oxide to whichhas been added di- 'phenylene oxidein the approximate ratio of t 7Oparts of'diphenyl oxide to parts byweight of diphenylene'oxide. a The method of stabilizing diphenyloxideat high'temperatures which consists in n adding thereto diphenyleneoxide. y

4;. The method-of stabilizing diphenyl oxide against decomposition athigh temperatures which consists in adding thereto di-' phenylene oxide.f

3 f 5. The method of stabilizing diphenyl oxide at'high temperatureswhich consists in adding to the diphenyl oxide, diphenylene 1 oxideinthe ratio of 30 or less parts of diphenylene oxide in a hundred partsof the I 40 resulting mixture.

6. A composition of matter" comprisingdiphenyl oxide to which, has been1 added e diphenylene oxide.

7. A composltion of matter-consisting of 445 .diphenylfoxide to whichhas been added ap- 5U idle and diphenyl.

proximately thirty per cent by'weight of diphenylene oxide. '7

' 8; A composition of matter consisting of a mixture of diphenyloxide,diphenylene ox- 9. Acomposition of matterconsisting of; a mixture ofdiphenyl oxide, diphenylene oxide and naphthalene. V 1

Signed by me this 10th day of J uly, 1929. v. V HERBERT H. DOW.

